Electric switch



June 3, 1930. H. A. DOUGLAS 1,761,434

ELECTRIC SWITCH Filed Dec. 21, 1927 Patented June 3, 1930 UNITED, STATES PATENT OFFICE -H.ARRY A. DOUGLAS, OF BRONSQN, MICHIGAN ELECTRIC swrrcn application filed December 21, 1927. Serial No.%1,641.

. My invention relates to electricswitches and in accordance with' one feature thereof, a contact member is7s'pring pressed into nor- -mally'permanent engagement with a circuit terminal to constitute an electrical continuation of such-terminal, this contact member being movable into and out of engagement with a complemental contact or terminal.

In accordance with another feature of the invention, a fulcrum is provided for such contact member andmeans are employed for relatively shifting the fulcrum and the place 4 of contacting engagement of the contact member whereby the circuit opening and closing. movements'of the contact member may be .rapidly effected.

The invention will be more fully explained in 'connection with the accompanying drawing in which Fig. 1 is a vertical sectional View illustrating a'form of the invention, showingthe switch in a circuit opening adjustment; Fig. 2 is a sectional view on line 2-2 of Fig. 1; Fig. 3 is a plan view showing a mounting panel in section; Fig. 4 is aview similar to Fig. 3 but showing thecasing in section and parts broken away; Fig. 5 is a sectional view on line 5- 5 of Fig. 1; and Fig. 6 is a view, partially in section and partially in elevation, showing the switch in a circuit closing adjustment.

The switch structure illustrated includes a casing 1 which is fixed upon the inner end of an exteriorly threaded bushing 2 which is held in place by means of nuts 3 and 4 screwed thereon and between which the dash board 3 or other mounting is clamped. The casing 1 is of inverted cup shape, the lower end of the casing beingclosed by a disc 6 of insulation. The circuit wires 7 and 8 are suitably connected with circuit terminals.

The circuit terminal with which the wire7 is connected includes a metallic post 9-pass ing through the disc 6 and having flanges 10 and 11 uponitsends and between which the disc is tightly received, a binding screw 12 for clampingthe wire in place, and'the metallic leaf extension 13. Said leaf extension has a cup shapedportion 13' constituting a socket which receives the outer end of the metallic contact plunger 14 whose outer end,

is rounded to conform to the shape of said socket whereb tact is pressed into engagement with the socket b means of the metallic coiled springspring barrel 16 whenthe wires 7 and 8 are to be connected, means being-provided for oscillating the spring barrel into and out of engagement with said flange 18. The spring barrel is desirably mounted in a carrier 21 of insulatiom-this carrier being enlarged at its upper end to receive the lower and rounded edge of a rectangular fulcrum plate 22 whose top edge engages the top of the casing 1 which holds this platefrom rotation.

The fulcrum is shifted by the stem 23 of' a.

reeiprocable handle 24, this stem sliding in the bore of the bushing '2. When the stem is in'its'innermost position, the fulcrum is 1 .npon the right. of e place of engagement of the contact plunger 14 with the .terminal portion 13 and when the stem is in its outer- 'most position, thefulcrum is upon the left of such-place of engagement. The fulcrum "and handle stem are desirably assembled by providing the stem with a peripheral "annular groove 25that receives the fulcrum plate, the fulcrum plate, itself, being formed with a slot 26 which receives the handle stem said plunger contact may readily be bodlly turned. The plunger conin the zone of the groove 25. This assembly of the handle stem and fulcrum plate permits the handle to be turned without damage and without effecting any circuit change, though it is understood that the invention is not to be limited to a structure in which the circuit changing movements areeffected by a reciprocable handle;

Changes may be made without departing from the invention.

Having thus described my invention, I claim:

1. In an electric switch, the combinatlon with. two circuit terminals; of a contact member which is inclusive of a compressible spring, a plunger contact pressed upon by the spring and having rocking engagement with oneof said circuit terminals, and a carrier for said lunger contact and spring; and a reciproca le handle having a fulcrum formation engaged by said carrier and upon which the carrier may turn in response to reciprocation of the handle, the handle being shiftable to bring the fulcrum formation thereon upon one side or the other of the place of engagement of the plunger contact and the clrcuit terminal uponwhich the plunger contact may rock, the aforesaidspring maintaining said carrier in engagement with said fulcrum formation in all positions of the handle, whereby the contact member has the final portions of its alternative movements quickly completed, the other circuit terminal being positioned to be en aged by said contact member when this memlier is in one of its alternative positions.

2. 'In an electric switch, the combination with a current conducting contact in the form of a spring barrel; of a plunger projecting from said spring barrel; 2. spring within the spring barrel and pressing outwardly upon the plunger; a, member upon which said plunger is pressed by the spring and upon which the lunger is turned, together with the spring arrel, by the spring; a contact complemental to the spring barrel contact and enga ed thereb when the latter contact is turned y the spring; and a switch handle operable upon the spring barrel and plunger to cause the same to turn and servin to separate the spring barrel contact from t e other.

3. The structure of claim 2 wherein the plunger and the member upon which the plunger turn's are current conducting contacts.

In witness. whereof, I 'hereuntosubscribe my name. HARRY A. DOUGLAS. 

